Body coupled communication (BCC) allows exchange of information between devices that are located at or in close proximity of a body of, for example, a user. The BCC signals are transmitted via the body instead of via a wire or instead of via radio signals. The signal is transmitted via low-energy electrical fields that are capacitively or galvanically coupled onto the body surface. The low-energy electrical field is coupled to the body via couplers, which are, for example, electrodes. Sometime the term antenna is used in the field of BCC for identifying the couplers, however, in BCC no radio signals are transmitted via the couplers and only a low-energy electrical field is generated or received via the couplers. BCC is possible when the body of the user is in the direct vicinity of the couplers of the device and capacitive or galvanic coupling between the device and the body is the basis for the transmission of signals. In other embodiment, the body may be in direct contact with the couplers. BCC has some specific advantages, such as: the amount of energy used in body coupled communication is relatively low and the signals of the body coupled communication can only be received (and transmitted) by devices which are in the direct vicinity of the body which forms the transmission channel of the body coupled communication. Thereby the coverage area of the body coupled communication is confined.
In published patent application WO2010/049842A1 an exemplary communication apparatus for and a method of receiving a body coupled communication signal has been disclosed. Although the amount of energy used in body coupled communication is relatively low, the communication apparatus of the cited prior art may still use too much energy. Especially in the field of BCC relatively small devices, such as a wrist watch, a mobile phone, etc. may be used in the communication system and such devices have in general limited energy resources.
In published patent application US2011/0299512A1 a communication device including a first communication unit for performing communication by a communication scheme is provided. The communication scheme is for applying voltage from a signal electrode that is in contact with or that is brought into proximity of a human body and for generating an electric near field on a human body surface and performing transmission. A second communication unit is different from the first communication unit and comprises a switching signal detection unit for detecting, from signals intermittently received by the first communication unit, a mode switching signal for switching the second communication unit from a power save mode to a normal mode, and a switching control unit for switching the second communication unit from the power save mode to the normal mode in a case the mode switching signal is detected by the switching signal detection unit.